The insecticide deltamethrin ("Synthetic insecticides with a new order of activity", M. Elliot et al., Nature, 248, 710-711, 1974) is prepared from both of the enantiomerically pure trans isomers of chrysanthemic acid using the resolved enantiomers and separate processing steps for each enantiomer. The pure enantiomers of trans chrysanthemic acid, in turn, are prepared from the racemic mixture of their diastereomeric salts by crystallization ("Evolution of an industrial process: deltamethrin synthesis", J. Tessler, Chemistry and Industry, 199-204, 1984).
The stereospecific hydrolysis of esters by enzymes from animal sources, especially from the livers of various species, has mainly concentrated on the use of enzymes from porcine liver ("Enzymes in organic synthesis", J. B. Jones, Tetrahedron, 42, 3351-3403, 1986 and the references cited therein).
The enzymes from the livers of other species have been used only in a limited number of cases for sterospecific hydrolysis. For example, enzymatic resolution of bicyclic lactones using horse liver enzyme has recently been reported ("Enzymatic resolution of bicyclic lactones by horse liver enzyme", E. Guibe et al., Tetrahedron Letters, 30, 67-68, 1989).
The hydrolysis of esters of chrysanthemic acid by enzymes from porcine liver was reported in the literature ("Enzymatic syntheses of Chiral building blocks from racemates: Preparation of (1R, 3R) - Chrysanthemic, - Permethrinic and -Caronic acids from racemic, diastereomeric mixtures", M. Schneider et al., Angew, Chem. Int. Ed., Engl., 23, 64-66, 1984).
Because of the commercial importance of trans chrysanthemic acid for use as an intermediate in the preparation of insecticides such as deltamethrin and other pyrethrin insecticides, and because only certain optical isomers are active, alternative methods are needed to effect the separation of chrysanthemic acid's geometric isomers as well as simultaneously achieving high resolution of its enantiomers.